[Heathkit] Need xtal set id info

[pmills7 at houston.rr.com]

Hello,

In sorting through a large box of Heathkit crystals, I came across a number 
of sets of 4 crystals.
One set consists of 2 each 3394.400 kc and 2 each 3396.750 kc.  The other 
set has 2 each 3395.450
and 2 each 3395.150.  Can anyone tell me what equipment these might be used 
in?

thanks, 73, Phil
W5BVB